Optical fiber SPR magnetic field sensor based on photonic crystal fiber with the magnetic fluid as cladding

Abstract

In this paper, a novel optical fiber surface plasmon resonance (SPR) magnetic field sensor is proposed and experimentally demonstrated. The structure is fabricated by splicing a section of photonic crystal fiber between two multimode fibers. After the structure is coated with 10 nm Cr and 50 nm Au, the high refractive index (RI) sensitivity, from 1973.72 nm RIU−1 to 3223.32 nm RIU−1 in the range of 1.3326–1.3680, verifies the SPR sensor, which is higher than the structure based on single mode fiber with the same coating. In addition, the microscopic mechanism of the tunable characteristics of magnetic fluid RI with the ambient magnetic field is simulated by the molecular dynamics method. To measure the external magnetic field, the sensing region of the SPR sensor is fully inserted in a capillary tube, which is filled with magnetic fluid and sealed with UV glue. A maximum sensitivity of 4.42 nm mT−1 is achieved in the range of 0–24 mT, experimentally. Due to high sensitivity, simple manufacturing and compact size, the proposed sensor possesses attractive application prospects in environmental monitoring, power transmission and biomedical applications.

Research Progress on Magneto-Refractive Magnetic Field Fiber Sensors

“…For this point, a common method is employing a fiber with a large mode field. For instance, Zhu et al [ 62 ] exploited a Multi-Mode Fiber (MMF) and a PCF’s fusion collapse region to induce the fiber Evanescent Field ( Figure 8 a). Evanescent Waves interact with Cr-Au films and MF, resulting in the generation of SPR.…”

“… Magnetic field fiber sensors based on SPR with ( a ) MMF-PCF-MMF structure [ 62 ] and ( b ) HMMs (reprinted with permission from Ref. [ 33 ], 2022, Springer Nature).…”

Multiparameter sensor based on micro/nano-structured optical fiber and composites

“…Notably, optical fibers and their composite structures have been widely used to monitor various parameters in the field of optical fiber sensing, such as: magnetic field, temperature, strain, displacement, acoustic vibration, etc. [4] , [5] , [6] , [7] , which is applied to construction and engineering health monitoring, power system monitoring and so on [8] , [9] . Among, in the field of power system monitoring, optical fibers possess many unique advantages versus other transmission media, such as: small size, light weight, anti-extreme environment, low-loss long-distance transmission, anti-electromagnetic interference, etc.…”

“…In the existing optical fiber sensors, different optical fiber structures have different measurement principles, such as: fiber grating-based sensing, surface plasmon resonance sensing, fiber-optic interference sensing, etc. [4] , [6] , [11] , [12] .…”